When the mold is designed, the concave and convex die should not be added to the manufacturing toler

Whether it is a convex and concave die or a core cavity.

I have just designed a plastic mold, and there is a part of the calculation of the molded part in the manual

The accuracy grade of the plastic part is general accuracy, (6 grades), so the manufacturing tolerance is selected as 1 4 of the tolerance of the part, and the mold wear coefficient is. The calculation process of the size of the working part of the mold is as follows:

a1m+δz =[(1+s)as1-xδ1]+δz1=[(1+a2m+δz =[(1+s)as2-xδ2]+δz2=[(1+b1m-δz =[(1+s)bs1+xδ3]-δz3=[(1+b2m-δz =[(1+s)bs2+xδ4]-δz4=[(1+b3m-δz =[(1+s)bs3+xδ5]-δz5=[(1+cm δz =[(1+s)csδz 2=[(1+superscript can't be seen, -δz, δz1,+These are all superscripts, 1 4 is the manufacturing tolerance, it's a mess, you probably don't bother to look at it, anyway, in a word, it is theoretically to be calculated.

Want. There is a requirement for precision in doing this.

The clearance of various materials is not the same. The unilateral ordinary blanking clearance of stainless steel is 8% For materials such as tinplate, the ordinary unilateral blanking clearance is 5%, and the ordinary blanking clearance of aluminum and copper is 3%-4%.

Stamping die is a special process equipment that processes materials (metal or non-metal) into parts (or semi-finished products) in cold stamping processing, which is called cold stamping die (commonly known as cold stamping die). Stamping is a pressure processing method that uses a die installed on a press to apply pressure to the material at room temperature to produce separation or plastic deformation, so as to obtain the required parts.

The clearance of various materials is not the same, the unilateral ordinary punching gap of stainless steel is 8%, the ordinary unilateral punching gap is 5%, and the ordinary blanking gap of aluminum and copper is 3%-4% If it is fine blanking, then basically the gap is very small, and the gap varies from wire to wire, depending on the thickness of the material, the softer the material, the smaller the gap.

In the process of stamping die, the size of the gap of the convex and concave die has a decisive influence on the quality and effect of the final workpiece, the mold is in the stage that needs to be carried out before stamping, and the smooth development of the assembly work and the effect of the assembly have greatly affected the mold effect of the final workpiece.

Generally, 10% of the material is taken, and the softer the material, the smaller the gap.

Hard material t<1mm unilateral clearance (6-8)%t

t=1-3mm, unilateral clearance: (11-17)%tt=3, 5mm, unilateral clearance: (17-25)%t, hard materials, refers to steel, iron, etc.

The tolerance design of punch and die in the mold needs to be designed according to the actual situation and the tolerance requirements of the product, and the shear tolerance of the hardware mold is generally determined according to 10% of the plate thickness.

The tolerance of the stamping die depends on the product, and the drawings for your parts will have important part tolerances, hole sizes, flatness, etc. For example, 8 holes are + to +, then you can only be between this, the book will not specify how many holes, the specific parts are different, there are no special provisions for general automobile stamping dies Round holes are added on the basis of diameter, there are regulations, such as reference holes and the like must be within the specified tolerance.

Dimensional tolerance is the error of the size of the part itself, such as length, width, height, diameter and height of the hole, etc., while the shape tolerance is related to the error of positioning position, such as the position of the hole (distance from the center line), etc.

In general, the geometric tolerance (value) is 1 3 or less than the dimensional tolerance. Because the tolerance in the example is very large, and the end face of the machine tool when processing the end face of the cylinder is fully jumped, it can be "easily" guaranteed to be within.

Because geometric tolerances are "much less" than dimensional tolerances (otherwise, they don't make sense), geometric tolerances are included in the dimensional tolerances. In the case of the principle of independence (except for the principle of inclusion), the dimensional tolerances must be qualified, and the geometric tolerances must be qualified.

Please see the stamping die design manual.